Method of making, filling, and sealing sterile containers formed of fibrous material



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METHOD OF MAKING, FILLING, AND SEALING STERILE CONTAINERS FORMED OF FIBROUS MATERIAL Filed Oct. 8, 1947 3 Sheets-Sheet 3 IN VEN TOR. IEAAIZ LANELL 0x ATTEIRNEYE United States Patent METHOD OF MAKING, FILLING, AND SEALING STERILE CONTAINERS FORMED OF FIBROUS MATERIAL Isaac L. Wilcox, Fulton, N. Y., assiguor to Oswego Falls Corporation, Fulton, N. Y., a corporation of New York Application October 8, 1947, Serial No. 778,620

4 Claims. (Cl. 53-10) This invention has to do with the manufacture, filling and sealing of containers made of sheet fibrous material, such as paperboard, and has as an object a method by which such containers, used for the packaging of food products, are rendered sterile prior to the time that the contents is placed in the container, and the container closed with a sterile end closure.

A container of the type herein referred to is disclosed in Patent No. 2,470,984, issued May 24, 1949, to Homing & Wilcox, and which consists of a tubular body portion formed from a flat blank of sheet fibrous material, such as paperboard, and onto each end of which is sealed an end closure formed of the same material. These containers are intended primarily for the packaging of liquid food products, such as milk.

It is well known that, over a substantial period of years, milk has been packaged in glass bottles for the retail trade. There are many well recognized advantages in packaging food products, especially milk, in paper containers, and of late a great deal of efiort has been put forth to devise a practical method of packaging milk in single use paper containers. There are, at the present time, a number of paper milk bottle installations in operation. However, a number of problems still exist in connection with such installations, one of the chief problems being that the paper bottles, or containers, may not be sterile at the time they are filled with milk. Various boards of health have called attention to this situation but, because of the nature of the material and the methods by which the bottles are fabricated and handled, no practical method has heretofore been worked out by which the containers can be fabricated, filled and sealed, in a sterile manner.

The paper milk containers in use today are fabricated from blanks into complete, or partially completed container form, and the containers are then coated with paratfin to render them liquid tight. This coating is applied by immersing the completed, or partially completed, container in a bath of molten parafiin wax. This, however, does not assure that the container will be sterilized. It is not possible to obtain complete sterilization by that method because no practical paraffin temperature, or time of application is lethal to pathogenic bacteria. The practical temperature of paraffin application is in the neighborhood of 185 F. To obtain sterilization at this temperature, it would be necessary to maintain the containers in the parafiin bath for an extended period of time and to this must be added the time necessary to cool the coated container after it leaves the paraffin bath. Thus, to apply the paraffin coating in a manner to approach sterilization of the container would result in slow production with excessively large and costly equipment. It would accordingly be impractical to carry out such a procedure in the dairy or packaging plant. If the containers are completed and waxed in a container manufacturing plant and shipped to the dairy for later use, there is a likelihood that the containers may become contaminated before being used.

Heretofore, metal and glass food containers have been treated with sterilizing heat prior to filling. However, that method is impractical in connection with present paper containers. The wax coating would soften and become ineffective long prior to sterilization of the coutainer. Also, the overlapping portions of fibrous containers are usually secured together with an adhesive and the application of heat to the completed container would tend to loosen the seams. with the result that the con- 1:31.11?! would be rendered unfit for use, or would develop ea s.

I have found that it is also very difiicult and impractical to treat the fibrous sheet uncoated, due to the fact that the bacteria apparently enter the interstices in the fibrous material and thus escape the effect of the sterilizing medium.

In carrying out my method, it is contemplated that the paper bottle is fabricated, filled and sealed, in the dairy or packaging plant. In this connection, the dairy is furnished with a supply of coated blanks from which the containers are fabricated. These blanks may be so formed with foldable portions that the entire container, including the body portion and the end closures, are fabricated from a single blank or, separate blanks may be supplied for the body and the end closures. However, as previously stated, the structural arrangement of the container is not of particular importance in carrying out my method.

The blanks are coated on at least one entire surface with an impervious material which, at normal tempera tures, is non-tacky and impenetrable, and which may be subjected to high surface temperatures for a short duration without adversely affecting the material. Certain of the synthetic. thermoplastic materials are suitable for this purpose such, for example, as the Series V Vinylite consisting of the copolymer of vinyl chloride and vinyl acetate. This material presents an impervious, glass-like surface into which bacteria can not penetrate. The blanks may be individually coated, or they may be blanked from a sheet or web which has been previously coated. In either case it will, of course, be understood that the blanks are fabricated into containers after the applied coating has properly dried. In the fabrication of the container, this coated surface is arranged inwardly forming the interior surface of the completed container. The coating serves. to, render the container impervious to the liquid contents, :and may also serve to effect proper adhesive seal for the overlapping, or abutting, portions of the container.

In the fabricating of the container, the coated surfaces of the blanks are subjected to heat until sterile. The time required toeffect sterilization of the coated surfaces of the container parts is of short duration due to the fact that any bacteria present are completely exposed on the impervious coated surface and are therefore completely subjected to the effect of the sterilizing heat, and are substantially instantaneously destroyed.

While the blank, or blanks, are in a sterile condition, they are processed to form the container with one end open, and the sterile open-ended container is immediately presented to the filling apparatus and immediately, upon being filled, the container is closed, either by applying to the open end of the container an end closure which has also been sterilized by heat during the filling operation or, by manipulating end closure forming tabs integral with the container, if the structure is of that form.

In the accompanying drawings, Figure l is a schematic illustration of a succession of operations in carrying out my method.

Figure 2 is a schematic arrangement for carrying out the operations illustrated in Figure 1.

Figure 3 is a schematic illustration of the operations in carrying out the method with a modified container construction.

In Figure l of the drawings, I have schematically illustrated the succession of operations in carrying out the above described method. The coated body blanks 10 are advanced to the right from position A to position B. At position B, the blanks are subjected to sterilizing heat and advanced to position C where they are formed into tubular container bodies 11.

Simultaneously with performing these operations on the body blank, end closure blanks 12 are likewise advanced to a heating zone and thence to a forming and applying zone or station, with the heated blanks 12 arranged in juxtaposition to the tubular body 11 and at this position, the blanks 12 are formed into end closure form 13 and applied and sealed to the end of the body 11 and the body with the end closure thereon advanced to position D. The containers are then advanced to a position E where they are filled by a filling device indicated at 14. While the containers are being tilled, end closure blanks 15 are subjected to heat and are advanced in juxtaposition to the filled container which has also been advanced to station E. At this station, the end closure blank 15 is shaped into end closure form 17 and applied to the container to close the open end thereof, and the filled and closed container advanced to a discharge station G.

In Figure 2 of the drawings, I have schematically illustrated an arrangement for carrying out the method-in forming, filling and closing a container of the type disclosed in the Homing & Wilcox patent above referred to. In this arrangement, a procession of container body blanks 10 are advanced into juxtaposition with a series of mandrels 18 carried on a turret 19 intermittently indexed. The blanks 10 may be arranged in a stack forrnationZt) with the coated sides downwardly and from which they are successively fed by any conventional blank feeder to a conveyor 21. As the blanks are advanced by the 'conveyor, the under sides of the blanks are subjected to heat from radiant heaters 22.

As the blanks 10 are successively moved into juxtaposition with the respective mandrels 18, the turret 19 is intermittently rotated and the blanks are folded, or wrapped, about the mandrels 18 at position B, with the edges of the blank overlapping and sealed together to form the tubular body member Ill with the coated side inwardly, or next to the mandrel. Simultaneously with the advancement of the body blanks 10 by the conveyor 21, a procession of end closure blanks 12 are advanced by a conveyor 25 to a forming and applying head 26. The end closure blanks 12 may likewise be arranged in a stack formation 27 and successively fed to the conveyor 25 and, while being advanced thereby, are subjected to heat from radiant heaters 28.

With this arrangement, as the tubular bodies 11 reach the vertical position C, a sterile end closure blank 12 is folded or shaped to end closure form 13 and applied and sealed to the outer end of the tubular formation by the head 26. There is accordingly at this timefabricatcd an open ended container. the containers reach the lowermost position in the path traveled by the 'rnandrels 18, as indicated at D, the container is removed from the mandrel and deposited upon a container conveyor 3% with the open end upwardly. The containers are advanced in a procession by the con veyor 30 and as they are advanced to the station E, they are filled by filling apparatus indicated at 14.

During the filling operation, a second series of end closure blanks are advanced by a conveyor 32 and, during their advancement, these blanks are subjected to heat from the radiant heaters 33. These blanks are advanced to an end closure forming and applying head 34 and as the filled containers are advanced to the station F, the sterilized blanks 15 are successively formed into end closures 17 and sealed to the tops of the containers by the head 34.

It will be understood by those familiar with the container fabricating art that the various operating parts of such an arrangement including the blank feeders, conveyors, applying heads etc., are operated in proper timed relation, and also that the method may be carried out with other structural arrangements depending upon the specific structure, or formation, of the container.

In Figure 3 of the drawings, I have schematically illustrated the succession of operations in carrying out the method in respect to a container, the body and end closure portions of which are formed from an integral blank. In this instance, the blank 36 is provided with score lines defining a series of central panels forming the tubular body portion 11, a series of tabs at one end corresponding to the blanks l2 and which are foldable to form a bottom closure 13. At the opposite end of the blank 36, the score lines define another series of tabs corresponding to the blanks 15 of the previously described arrangement and which are foldable to form a top closure 17.

The blanks 36 are similarly coated and subjected to sterilizing heat while transferred from position A to position B and at position B, the central panels are folded to form the tubular body 11. Thereupon, the tabs 12 are folded to form the bottom closure 13 presenting an open ended container at position C. This container is advanced to position E where it is filled by the filling apparatus 14. The upper tabs 12 are then folded and sealed to form the top closure 17, as illustrated at position F.

The important features of the invention reside in the sterilizing of the body and end closure portions previous to their formation into a container, filling the container while sterile, and applying the sterile top closure.

What I claim is:

1. The method of manufacturing, filling and sealing sterile containers formed of sheet fibrous material consisting in simultaneously subject-ing a fiat body blank and a fiat end closure blank to heat until sterile, forming the body blank into a tubular body, forming the end closure blank into an end closure and applying the same to the end of the tubular body, filling the container while sterile and while filling subjecting a second flat end closure blank to heat until sterile and, upon completion of the filling operation, forming the sterile blank into end closure form, and sealing the same to the open end of the container.

2. The method of making, filling and sealing sterile containers formed from substantially flat blanks of sheet fibrous material consisting in coating one entire surface of a body blank and end closure blanks with an impenetrable substance capable of withstanding temperatures lethal to bacteria, advancing the body blank and one end closure blank simultaneously in heat exchanging relation to radiant heat until the coated areas of the blanks are sterile, forming the body blank into a tubular body formation,

' forming the closure blank into an end closure and sealing As the turret 19 is indexed and the same to one end of the body, thereupon filling the container and while filling advancing a second end closure blank in heat exchanging relation to a radiant heat, forming said second blank to an end closure, and sealingthe same to the open end of the container.

3. The method of manufacturing, filling and sealing sterile containers formed from substantially flat body and end closure blanks of sheet fibrous material consisting in coating one entire surface of a body blank and end closure blanks with an impervious substance, subjecting the coated surface of the body blank and simultaneously subjecting one closure blank to heat until sterile, forming the body blank into a tubular body formation, forming the end closure blankinto an end closure and sealing the same to one end of the body formation, filling the container and while filling subjecting the coated surface of the second end closure blank to heat, forming said second blank into end closure form, and sealing the same to the open end of the container.

4. The method of making sterile containers from flat body and end closure blanks of sheet fibrous material, the improvement consisting in coating one surface of the body and end closure blanks with an impenetrable substance capable of withstanding high temperatures lethal to bacteria, advancing a procession of the flat body blanks through a high temperature sterilizing z'one until sterile, advancing a procession of fiat end closure blanks through a high temperature sterilizing zone until sterile, forming said sterile body blanks successively into tubular bodies, forming said sterile end closure blanks into end closures and sealing the same to the ends of said tubular bodies, advancing a second procession of fiat end closure blanks through a high temperature sterilizing zone and forming and sealing said blanks to the open end of the containers.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,174,692 Cooley Mar. 7, 1916 1,270,798 Dunkley July 2, 1918 2 174,514 I-Iothersall Oct. 3, 1939 2,223,754 Waters Dec. 3, 1940 2,296,895 Bergstein Sept. 29, 1942 2,332,099 McKinnis -2 Oct. 19, 1943 2,392,395 Lehman Jan. 8, 1946 2,433,056 Masci Dec. 23, 1947 

